Endocrine disrupting chemicals, so-called environmental hormones, have become a focus of worldwide social interest since their existence was shown in Our Stolen Future (Japanese title: Ubawareshimirai, 1st Edition issued in 1996, revised in 2001) by Theo Colborn et al. A great number of chemical substances suspected to have an endocrine disrupting activity have been known, chemical substances including polychlorodibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and co-planar polychlorinated biphenyls (cPCBs) were defined in Japan as the dioxins by Law Concerning Special Measures against Dioxins published in July, 1999. The dioxins have a very high toxicity. Known acute toxicity includes dermatitis, hepatopathy, neuropathy, immunologic toxicity and the like, and suspected chronic toxicity includes teratogenicity, embryotoxicity, carcinogenicity, xenobiotic metabolic enzyme induction and the like. It is estimated that the amount of the dioxins to which a human is exposed in the daily life is at a level of about 2.3 pg-TEQ (toxic equivalent quantity), which is far lower than the amount showing acute toxicity. However, since it is known that the dioxins are remained and accumulated in the adipose tissue in the living body, there is a possibility that they act like internally synthesized hormones at a concentration lower than the toxically active concentration. This activity is the reason why the dioxins are called environmental hormones.
Most of the dioxins are released to the environment through an unintentional production process. cPCBs were contained as by-products in polychlorobiphenyls (PCBs) used in a great amount in electric parts and the like owing its incombustibility and insulative property, and resultingly, was continuously released to the environment even after its production was prohibited in 1971. While the dioxins are very slowly decomposed in the environment, they are taken into living bodies of various organisms during the decomposition period and bioconcentrated within the food chain. It is afraid that humans are unavoidably exposed to them by taking polluted organisms as food.
There are many unclear points relating to absorption, metabolism and exclusion of the dioxins in living bodies. Since the dioxins are oil-soluble, they are transferred to the adipose tissue after taken in the body as described above. Particularly, in liver, expression of a specific gene is induced by a signal transduction pathway through a receptor. Especially, it has been shown that, when cytochrome P450 protein is expressed, the dioxins are hydroxylated or reductively dehalogenated by its enzymatic activity. Thus, it is considered that the dioxins are excluded to the outside of the body owing to enhancement of water-solubility by such metabolism and through secretion into the bile.
On the other hand, microorganisms such as lactic acid bacteria used for fermented milk and Bacillus subtilis used for fermented soybeans (natto) have been widely utilized in foods and feeds, and it is known that many advantageous activities were brought about to a host by their cells and fermentation products. Particularly, lactic acid bacteria, Bacillus subtilis and bifidobacteria contribute to health of the host by directly or indirectly acting on intestinal flora and eliminating harmful bacteria. In addition, as an activity without relating to intestinal flora, it is known that a peptide as a fermentation product has an antihypertensive activity. Inventions in which lactic acid bacteria give advantageous activities to liver function include a lactic acid bacterium which lowers liver cholesterol (JP-A-7-250670), a fermentation product of an enzymatically treated rice bran lactic acid bacterium which relieves hepatopathy caused by stress (JP-A-9-132533), an intestinal infusion solution containing Lactobacillus plantarum and arginine in combination (JP-A-11-504936) and the like. However, no microorganisms relating to elimination of environmental pollution substances to the outside of the living body have been known.
An object of the present invention is to provide an accelerating agent for elimination of dioxins, which comprises, as an active ingredient, a microorganism having an activity of accelerating elimination of dioxins accumulated in the body such as liver to the outside of the body. Since the dioxins are unconsciously taken from foods, the air, water, soil or the like, and its intake is difficult to avoid, and it is important that the active ingredient is used in daily eating in humans and is a feed additive routinely usable in edible livestock.